"Our results point to an option to use Pycnogenol as a natural supplement to relieve ADHD symptoms of children," wrote lead author researcher Jana Trebatická in the journal European Child and Adolescent Psychiatry (doi: 10.1017/s00787.006-0538-3).
ADHD is thought to affect between three to seven per cent of children in the UK, with the problem continuing into adulthood for as many as 60 per cent of sufferers. Boys are reported to be three times more likely than girls to suffer from ADHD, according to the National Attention Deficit Disorder Information and Support Service (ADDISS).
The new randomized, placebo-controlled, double-blind study assigned 57 children (average age 9.5 years) to receive either a daily supplement of the French maritime pine bark extract (1 mg/kg) or placebo (58 mg lactose, 65 mg cellulose) for one month.
Volunteers were evaluated at the start, end and one month after the end using a series of scales: The Child Attention Problems (CAP) teacher rating scale; the Connor's Teacher Rating Scale (CTRS); and the Connor's Parent Rating Scale (CPRS); and basic psychiatric examinations.
After one month of supplementation the researchers, from Comenius University in Slovakia and the University of Munster in Germany, found that the inattention and hyperactivity scores decreased by about 20 per cent for the pycnogenol group, but no changes for placebo, according to the CAP scores, evaluated by teachers.
The CTRS scores showed that inattention and hyperactivity scores decreased by about 10 and 15 per cent, respectively, for the pycnogenol group, but no changes for placebo.
The parental scores on the CPR scale also reported a decrease of about eight per cent and about 16 per cent for inattention and hyperactivity, respectively.
No significant changes were reported for the placebo groups.
"Our findings seem to present an alternative to existing drugs for parents fearing the adverse effects of established drugs, however, results of our study have to be further confirmed by studies involving a greater number of patients," wrote the researchers.
The mechanism behind the benefits of the French maritime pine bark extract is still to be identified, said the researchers. They did however propose that the extract might be promoting synthesis of nitric oxide (NO) synthase in the brain, a molecule reported to be a neurotransmitter.
In vitro and in vivo studies have reported that Pycnogenol stimulates NO synthase in the endothelium (smooth muscle lining blood vessels), but it is not known if NO synthase is stimulated in the brain as a result of the pine bark extract.
It should also be stressed that the role of NO in learning is highly controversial with apparent conflicting results to be found in the literature.
"The relative small number of patients and the short duration of the study limits the generalization of our findings," said the researchers.
Pycnogenol, made by Horphag Research and co-sponsors of this study, has been claimed to have beneficial effects on a wide range of medical conditions from diabetes to asthma. It has also been proposed to boost male fertility and improve the memory of mice.
The product is extracted from the bark of the Maritime pine that grows on the southern coast of France, and is currently used in over 400 dietary supplements, multi-vitamins and health products.